The Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario, Canada; Division of Pathology, Hospital for Sick Children, Toronto, Ontario, Canada.
The Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario, Canada.
Mol Cell Proteomics. 2022 Oct;21(10):100411. doi: 10.1016/j.mcpro.2022.100411. Epub 2022 Sep 9.
Chromatin structure, transcription, DNA replication, and repair are regulated via locus-specific incorporation of histone variants and posttranslational modifications that guide effector chromatin-binding proteins. Here we report unbiased, quantitative interactomes for the replication-coupled (H3.1) and replication-independent (H3.3) histone H3 variants based on BioID proximity labeling, which allows interactions in intact, living cells to be detected. Along with a significant proportion of previously reported interactions detected by affinity purification followed by mass spectrometry, three quarters of the 608 histone-associated proteins that we identified are new, uncharacterized histone associations. The data reveal important biological nuances not captured by traditional biochemical means. For example, we found that the chromatin assembly factor-1 histone chaperone not only deposits the replication-coupled H3.1 histone variant during S-phase but also associates with H3.3 throughout the cell cycle in vivo. We also identified other variant-specific associations, such as with transcription factors, chromatin regulators, and with the mitotic machinery. Our proximity-based analysis is thus a rich resource that extends the H3 interactome and reveals new sets of variant-specific associations.
染色质结构、转录、DNA 复制和修复是通过组蛋白变体的位置特异性掺入和翻译后修饰来调节的，这些修饰指导效应染色质结合蛋白。在这里，我们报告了基于 BioID 邻近标记的复制偶联（H3.1）和复制独立（H3.3）组蛋白 H3 变体的无偏、定量相互作用组，这使得可以在完整的、活细胞中检测到相互作用。除了通过亲和纯化和质谱检测到的大量以前报道的相互作用外，我们鉴定的 608 种与组蛋白相关的蛋白质中有四分之三是新的、未表征的组蛋白关联。这些数据揭示了传统生化方法无法捕捉到的重要生物学细微差别。例如，我们发现染色质组装因子-1 组蛋白伴侣不仅在 S 期沉积复制偶联的 H3.1 组蛋白变体，而且在体内整个细胞周期中都与 H3.3 相关联。我们还鉴定了其他变体特异性关联，如与转录因子、染色质调节剂和有丝分裂机制。因此，我们基于邻近的分析是一个丰富的资源，扩展了 H3 相互作用组，并揭示了新的变体特异性关联集。
